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* Copyright (c) 2008, Whiteboard-IT
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using System.Collections.Generic;

namespace Mite
{
	public class TableAlteration
	{
		private TableAlteration(Table table)
		{
			_table = table;

			NewName = null;
			ColumnsToAdd = new HashSet<Column>();
			ColumnsToRemove = new HashSet<Column>();
			ForeignKeysToAdd = new HashSet<ForeignKey>();
			ForeignKeysToRemove = new HashSet<ForeignKey>();
		}

		public string TableName
		{
			get { return _table.Name; }
		}

		public string NewName { get; private set; }
		public HashSet<Column> ColumnsToAdd { get; private set; }
		public HashSet<Column> ColumnsToRemove { get; private set; }
		public HashSet<ForeignKey> ForeignKeysToAdd { get; private set; }
		public HashSet<ForeignKey> ForeignKeysToRemove { get; private set; }

		/// <summary>
		/// Create a table alteration for <paramref name="table"/>.
		/// </summary>
		public static TableAlteration For(Table table)
		{
			Guard.ArgumentNotNull("table", table);

			return new TableAlteration(table);
		}

		/// <summary>
		/// Change the name of the table to <paramref name="name"/>.
		/// </summary>
		/// <param name="name">New name of the table.</param>
		public TableAlteration Rename(string name)
		{
			Guard.StringArgumentNotNullOrEmpty("name", name);

			NewName = name;

			return this;
		}

		/// <summary>
		/// Add <paramref name="column"/> to the table.
		/// </summary>
		public TableAlteration AddColumn(Column column)
		{
			Guard.ArgumentNotNull("column", column);

			if (ColumnsToRemove.Contains(column))
				ColumnsToRemove.Remove(column);

			ColumnsToAdd.Add(column);
			return this;
		}

		/// <summary>
		/// Remove <paramref name="column"/> from the table.
		/// </summary>
		public TableAlteration RemoveColumn(Column column)
		{
			Guard.ArgumentNotNull("column", column);

			if (ColumnsToAdd.Contains(column))
				ColumnsToAdd.Remove(column);

			ColumnsToRemove.Add(column);
			return this;
		}

		/// <summary>
		/// Add <paramref name="foreignKey"/> to the table.
		/// </summary>
		/// <param name="foreignKey">Foreign Key to add to the table.</param>
		public TableAlteration AddForeignKey(ForeignKey foreignKey)
		{
			if (ForeignKeysToRemove.Contains(foreignKey))
				ForeignKeysToRemove.Remove(foreignKey);
			ForeignKeysToAdd.Add(foreignKey);

			return this;
		}

		/// <summary>
		/// Remove <paramref name="foreignKey"/> from the table.
		/// </summary>
		public TableAlteration RemoveForeignKey(ForeignKey foreignKey)
		{
			if (ForeignKeysToAdd.Contains(foreignKey))
				ForeignKeysToAdd.Remove(foreignKey);
			ForeignKeysToRemove.Add(foreignKey);

			return this;
		}

		private readonly Table _table;
	}
}